*{
    margin: 0;
    padding: 0;
}


#app{
    width:100%;
    height: 100%;
    background: yellow;
    /* position: absolute; */
}

#left{
    /* display: none; */
    width: 210px;
    height: 100%;
    background: greenyellow;
    float: left;
    position: fixed;
}

#top{
    margin-left: 210px;
    height: 100px;
    background: hotpink;
    line-height: 100px;
}

#right{
    margin-left: 210px;
    height: 1000px;
    background: pink;
    /* position: relative; */
}

li{
    height: 50px;
    width: 210px;
    line-height: 50px;
}

iframe{
    width: 100%;
    height: 100%;
}